Beverage capsule with safety feature

ABSTRACT

The present invention concerns a capsule ( 12 ) for the preparation of a food or beverage by injection therein of a fluid under pressure, comprising a chamber containing a substance, a bottom pierceable membrane ( 23 ), and opening means ( 24 ) allowing the capsule to be opened by piercing the bottom membrane for allowing the beverage to flow out of the capsule, the opening means ( 24 ) comprising a surface with a multitude of piercing elements ( 25 ) which are configured to engage the bottom membrane ( 23 ) under the effect of the rise in pressure in the chamber, characterized in that said opening means ( 23 ) further comprises at least one safety piercing element ( 26 ) that is surrounded by a safety wall ( 27 ) such that the apex ( 28 ) of said safety piercing element is located within the vicinity of said safety wall ( 27 ).

FIELD OF THE INVENTION

The present invention concerns a capsule for food and/or beveragepreparation suitable for use with a beverage preparation machine, thatcomprises a built-in feature for emergency opening.

BACKGROUND OF THE INVENTION

Beverage preparation machines are well known in the food industry andconsumer goods area. Such machines allow a consumer to prepare at home agiven type of beverage, for instance a coffee-based beverage, e.g. anespresso or a brew-like coffee cup.

Today, most beverage preparation machines for in-home beveragepreparation comprise a system made of a machine which can accommodateportioned ingredients for the preparation of the beverage. Such portionscan be soft pods or pads, or sachets, but more and more systems usesemi-rigid or rigid portions such as rigid pods or capsules. In thefollowing, it will be considered that the beverage machine is a beveragepreparation machine working with a rigid or semi-rigid capsule.

The machine preferably comprises a receptacle for accommodating saidcapsule and a fluid injection system for injecting a fluid, preferablywater, under pressure into said capsule. Water injected under pressurein the capsule, for the preparation of a coffee beverage, is preferablyhot, that is to say at a temperature above 70° C. However, in someparticular instances, it might also be at ambient temperature, or evenat a chilled temperature. The pressure inside the capsule chamber duringextraction and/or dissolution of the capsule contents is typically about1 to about 8 bar for dissolution products and about 2 to about 12 barfor extraction of roast and ground coffee. The present invention couldalso encompass the so-called “brewing” process of beveragepreparation—particularly for tea and coffee. Brewing involves a time ofinfusion of the ingredient by a fluid (e.g. hot water), whereas theextraction or dissolution preparation process allows a consumer toprepare a beverage, for instance coffee, within a few seconds.

Generally, in the following specification, the term “brewing” of aningredient by a fluid, is meant to encompass extraction of a powderededible material such as for instance roast and ground powdered coffee,or dissolution of edible soluble material such as for instance solubletea or coffee, milk, cocoa mixes, or infusion of an edible material withan infusion fluid under very low relative pressure, or atmosphericpressure, for a longer time than that required for extraction ordissolution, for instance infusion of tea leaves by hot water.

The principle of extracting and/or dissolving the contents of a closedcapsule under pressure is known and consists typically of confining thecapsule in a receptacle of a machine, injecting a quantity ofpressurized water into the capsule, generally after piercing a face ofthe capsule with a piercing injection element such as a fluid injectionneedle mounted on the machine, so as to create a pressurized environmentinside the capsule either to extract the substance or dissolve it, andthen release the extracted substance or the dissolved substance throughthe capsule. Capsules allowing the application of this principle havealready been described for example in applicant's European patent no EP1 472 156 B1, and in EP 1 784 344 B1.

Machines allowing the application of this principle have already beendescribed for example in patents CH 605 293 and EP 242 556. According tothese documents, the machine comprises a receptacle for the capsule anda perforation and injection element made in the form of a hollow needlecomprising in its distal region one or more liquid injection orifices.The needle has a dual function in that it opens the top portion of thecapsule on the one hand, and that it forms the water inlet channel intothe capsule on the other hand.

The machine further comprises a fluid tank—in most cases this fluid iswater—for storing the fluid that is used to dissolve and/or infuseand/or extract under pressure the ingredient(s) contained in thecapsule. The machine comprises a heating unit such as a boiler or a heatexchanger, which is able to warm up the water used therein to workingtemperatures (classically temperatures up to 80-90° C.). Finally, themachine comprises a pump element for circulating the water from the tankto the capsule, optionally though the heating unit. The way the watercirculates within the machine is e.g. selected via a selecting valvemeans, such as for instance a peristaltic valve of the type described inapplicant's European patent application EP 2162653 A1.

When the beverage to be prepared is coffee, one interesting way toprepare the coffee is to provide the consumer with a capsule containingroast and ground coffee powder, which is to be extracted with hot waterinjected therein.

Capsules have been developed for such an application, which aredescribed and claimed in applicant's European patent EP 1 784 344 B2, orin European patent application EP 2 062 831.

In short, such capsules typically comprise:

-   -   a hollow body and an injection wall which is impermeable to        liquids and to air and which is attached to the body and adapted        to be punctured by e.g. an injection needle of the machine,    -   a chamber containing a bed of roast and ground coffee to be        extracted or a soluble beverage precursor ingredient, e.g. a        milk based powder or soluble powdered tea,    -   an aluminium membrane disposed at the bottom end of the capsule,        that hermetically closes the capsule, for retaining the internal        pressure in the chamber, this bottom membrane being associated        with piercing means for piercing dispensing holes in the        aluminium membrane when the internal pressure inside the chamber        reaches a certain pre-determined value,    -   optionally, means configured to break the jet of fluid so as to        reduce the speed of the jet of fluid injected into the capsule        and distribute the fluid across the bed of substance at a        reduced speed. It is often important for the user to know when        the water level in the machine tank is too low to prepare a full        beverage.

In many instances, the capsules for use in beverage preparation machinesare closed capsules as described above. Such closed capsules areinteresting because they protect the ingredient contained therein fromambient gas and moisture and allow long conservation time. Typically,such closed capsules are made from gas and/or moisture impermeablematerial and feature a rigid or semi-rigid body having a one of itswalls—for instance the top wall—made from a membrane which is to bepierced by the fluid injection needle of the beverage preparationmachine. When liquid is injected in the capsule compartment, a pressureis built up, which serves as an extraction means for extractingingredients contained inside the capsule through a dispensing wall ofthe capsule—typically the bottom wall—.

However, beyond their clear benefits for the consumer as describedabove, closed capsules may also raise certain issues.

It was found that in some—generally exceptional—cases, when the machinestarts injecting fluid (e.g. water) under pressure within the capsule,the opening of the membrane located at the dispensing side of thecapsule does not occur properly when fluid pressure inside the capsulebuilds-up. More precisely, it was found that in such cases, the capsuledispensing side opens, and in some cases, a few drops of product maystart to flow through the dispensing side of the capsule. However, dueto product characteristics, in particular, due to some aggregates ofundissolved ingredient, or due to big particles, the holes in thedispensing side of the capsule are almost immediately clogged in such away that the end product cannot flow properly therethrough towards aconsumer cup, as it should normally be the case.

As a first result, the beverage is not dispensed to the consumer, whohas to withdraw the blocked capsule from the machine, and replace itwith a new one. This withdrawal operation may however be messy, becausethe fluid inside the capsule is under pressure, and when the consumeropens the machine, the injection needle is removed from the top wall(e.g. top membrane) of the capsule, and fluid under pressure flows, orsometimes even sprays, out of the capsule, which is of courseundesirable.

More than that, in some instances, the beverage preparation machinecomprises a security, which prevents opening of its capsule compartmentuntil in-capsule pressure has not decreased to a predetermined value. Incase of capsule blockage, the machine cannot be re-opened, unless thecapsule is pierced using a piercing tool, for instance by accessing thedispensing pierceable membrane from below said capsule, which is alsoundesirable and not user-friendly.

Although such cases of blocked capsules are exceptional, it is highlydesirable to provide a solution which prevents capsule blockage. This isthe primary objective of the present invention.

SUMMARY OF THE INVENTION

The main objective set out above is met with a capsule for thepreparation of a food or beverage by injection therein of a fluid underpressure, comprising a chamber containing a substance, a bottompierceable membrane, and opening means allowing the capsule to be openedby piercing the bottom membrane for allowing the beverage to flow out ofthe capsule, the opening means comprising a surface with a multitude ofpiercing elements which are configured to engage the bottom membraneunder the effect of the rise in pressure in the chamber, characterizedin that said opening means further comprises at least one safetypiercing element that is surrounded by a safety wall such that the apexof said safety piercing element is located within the vicinity of saidsafety wall.

Importantly, and as explained above, it may happen that due to thecharacteristics of the substance initially contained in the capsulewhich is meant to be dissolved with a fluid injected inside the capsulefor making the final product, the normal dispensing openings created bypiercing of the bottom membrane by the piercing elements are clogged bybig particles and the dispensing flow stops (i.e. the capsule isblocked). In that case, the fluid pressure inside the capsule willcontinue to build-up as more mixing fluid (e.g. water) is injectedtherein, which will press onto the safety wall up to the point where itwill actually enter slightly into said wall vicinity and be pierced bythe safety piercing element contained therein. As it can be understood,in normal conditions where the product is dispensed outside of thecapsule, the internal pressure inside the capsule is not sufficient topush the bottom membrane inside the vicinity of the safety wall.Therefore, in normal conditions of use, the safety piercing element isnot used, as the regular piercing elements—which are not surrounded bysafety walls—are sufficient to create dispensing opening of the capsule.

It was found that the ratio “height of the safety piercing element, toheight of the safety wall” substantially determines the safety openingpressure, i.e. the opening pressure in case the normal opening of thecapsule does not occur. The higher the ratio, the lower the openingpressure will be. Also the height and shape of the safety piercingelement controls the opening pressure and opening time. This ratioshould be preferably comprised between 0.5 and 1, having regard to thefact the base of the safety piercing element and the safety wall are onthe same level. In other words, the safety piercing element should bedimensioned such that its height is comprised between half the size ofthe safety wall, and the full height of the safety wall (in that case,the apex of the safety piercing element is on the same level as theupper edge of the safety wall. Therefore, according to the invention thesafety piercing element never protrudes outside of the safety wallvicinity, and is therefore accessible to the bottom membrane of thecapsule only in cases where the pressure inside the capsule exceeds thenormal use pressure (in case the normal piercing elements do notfunction properly).

More preferably, the ratio “height of the safety piercing element toheight of the safety wall” should be comprised between 0.7 and 0.9.

Preferably, the surface of the opening means is at least partially openin its portion located between the safety wall and the safety piercingelement, such that fluid can flow between both sides of said surface.

The safety wall can be cylindrical, which is easier to manufacture byinjection moulding.

Preferably, the internal diameter of said safety wall is comprisedbetween 1 and 10 mm, preferably between 2 and 5 mm.

Also preferably, the apex of the safety piercing element is conical.

The piercing element can be hollow, or plain.

In a first embodiment of the invention, the safety piercing element andthe safety wall are integrally moulded with the opening means.

In a second alternative embodiment of the invention, the safety piercingelement is an independent element that is attached, welded, or similarlysecured inside the safety wall of the opening means.

In the latter case, the piercing element can advantageously comprise abase attached to the internal surface of the safety wall, said basehaving a cross section inferior to the corresponding inner cross sectionof said safety wall along at least one radial direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the description of thepresently preferred embodiments which are set out below with referenceto the drawings in which:

FIG. 1 is a schematic perspective view of a beverage preparation machineaccording to the invention;

FIG. 2 is a schematic enlarged perspective view showing the interior ofthe brewing head of a machine as illustrated in FIG. 1;

FIG. 3 is a schematic perspective cut view of a capsule according to theinvention;

FIG. 4 is a schematic perspective top view of a piercing plate accordingto the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention concerns a machine 1 of the type illustrated inFIG. 1. Such a machine 1 comprises a water reservoir 2, a brewing head3, a cup tray 4 that can be set at different heights relative to thebrewing head, control panel and buttons. In a possible embodiment, thecontrol buttons comprise more particularly a rotating wheel 6 and thecontrol panel is a screen 7. An ingredient capsule can be placed in acapsule holder 8 which is removably inserted into the brewing head 3.The screen 7 is suitable for displaying various information to theconsumer, for instance the volume level 9 that is dispensed in the cup.The user can also choose the temperature of the beverage that will beprepared, by actuating hot or cold buttons 11 which are present close tothe wheel and screen on the surface of the brewing head.

FIG. 2 represents schematically the internal configuration of anembodiment of a brewing head 3 in its open position. The capsule holder8 is loaded with a capsule 12. The capsule has a top pierceable membrane13, and top peripheral edge 14. The brewing head 3 typically comprisesan open/close mechanism with a handle 15 and a knee mechanism 16 thatmechanically links the handle to a support plate 17. The support plate17 carries an injection plate 18 that is moved in direct contact withthe peripheral edges 14 and top membrane 13 of the capsule in aleaktight manner, when the brewing head is in the closed position. Theinjection plate is a needle plate 18 that carries one injection needle19 to pierce through the top membrane of the capsule when the brewinghead is closed. The needle 19 is linked in a fluidic manner (via pipes)to the pump, heating element, and reservoir (elements not shown in thedrawing) of the machine.

As illustrated in FIG. 3, the capsule comprises a capsule side wall 20,a capsule top wall 13 which is a membrane sealed onto the surface of thetop peripheral edge 14 of the capsule, said membrane being pierceable bythe needle 19 for injection of water under pressure, as illustrated inFIG. 3. The capsule further comprises a bottom wall 21 having a bottomdispensing opening 22 through which the beverage prepared within thecapsule flows by gravity and is dispensed within a cup placed therebelow. The capsule is hermetically sealed by a flexible pierceablebottom membrane 23. The bottom membrane 23 can be for instance analuminium membrane coated with a thermoplastic on its lower surface soas to be sealable onto the inner surface of the capsule.

As shown in FIG. 4, the capsule 12 further comprises opening means 24comprising a surface with a multitude of piercing elements 25 which areconfigured to engage the bottom membrane 23 under the effect of the risein pressure in the capsule chamber. The piercing elements are preferablypyramid shaped with a cut apex.

According to the invention, and as illustrated in FIG. 4, the openingmeans further comprises a safety piercing element 26 that is surroundedby a safety wall 27. The height of the safety channel 27 relative to thesafety piercing element 26 is such that the apex 28 of said safetypiercing element is located within the vicinity of said channel 27 asshown in FIG. 4. The internal diameter of said safety channel is about 4mm. The safety piercing element and the safety channel are integrallymoulded with the opening means. The shape of the safety piercing elementcan be of any suitable shape such as a cone or a pyramid for instance.Preferably, the apex 28 of the safety piercing element is sharp. Thesurface of the opening means 24 is open with safety channels 29 so thatfluid can pass trough and flow through the dispensing opening of thecapsule.

During normal operation, the pressure builds-up within the capsule, andthe latter opens at its dispensing—bottom—side to let the beverage flowout into a cup placed below, as explained here above.

In case of a capsule blockage, when fluid pressure builds-up within thecapsule, its bottom membrane will flex downwards and its shape willtightly conform to the lower surface of the piercing plate, enteringinto the cylindrical chamber as well. It will then contact the apex ofthe piercing element, which will pierce said bottom membrane to releasethe pressure and unblock the capsule. The pressurized fluidadvantageously flows through the exit channels towards the dispensingopening of the capsule, as in a normal dispensing cycle.

By unblocking the capsule, the machine security—if one is present—isdisconnected, which allows the user to unlock the brewing head of saidmachine, and use it as usual.

It was found that placing the apex of the safety piercing elementslightly inside the cylindrical channel of the piercing plate, at adistance from the upper edge of said channel which is not greater than 1mm, and designing said channel with a diameter of between 2 and 5 mm,allows to guarantee that the bottom membrane of the capsule will flexdownwards and be pierced—in case of capsule blockage—when the fluidpressure inside the capsule is slightly above the maximum normal openingpressure of said capsule, i.e. at a pressure inside the capsule that iscomprised between 10 and 15 bar.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its attendant advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

1. A capsule for the preparation of a food or beverage by injectiontherein of a fluid under pressure, comprising a chamber containing asubstance, a bottom pierceable membrane, and an opening member allowingthe capsule to be opened by piercing the bottom membrane for allowingthe beverage to flow out of the capsule, the opening member comprising asurface with a multitude of piercing elements which are configured toengage the bottom membrane under the effect of the rise in pressure inthe chamber, the opening member comprises at least one safety piercingelement that is surrounded by a safety wall such that the apex of thesafety piercing element is located within the vicinity of the safetywall.
 2. A capsule according to claim 1, wherein the surface of theopening member is at least partially open with safety channels in itsportion located between the safety wall and the safety piercing element,such that fluid can flow between both sides of the surface.
 3. A capsuleaccording to claim 1, wherein the safety wall is cylindrical.
 4. Acapsule according to claim 1, wherein the internal diameter of thesafety wall is comprised between 1 and 10 mm.
 5. A capsule according toclaim 1, wherein the apex is conical.
 6. A capsule according to claim 1,wherein the safety piercing element is hollow.
 7. A capsule according toclaim 1, wherein the safety piercing element is plain.
 8. A capsuleaccording to claim 1, wherein the safety piercing element and the safetywall are integrally moulded with the opening member.
 9. A capsuleaccording to claim 1, wherein the safety piercing element is anindependent element that is attached, welded, or similarly securedinside the safety channel of the opening member.
 10. A capsule accordingto claim 9, wherein the safety piercing element comprises a baseattached to the internal surface of the safety wall, the base having across section less than a corresponding inner cross section of the wallalong at least one radial direction.